Proposals by Dublin City Council and the National Transport Authority to restrict vehicles from some parts of the city will result in a loss of business and reduce spending, opponents claim.

A survey of more than 1,000 shoppers by the Irish Parking Association (IPA), which represents the main car parks, has found that if the restrictions are put in place, they will result in a 24pc decline in overall revenues from shopping and entertainment.

The city centre was experiencing a "difficult trading environment" and measures to restrict access could exacerbate the problem," said the president of the IPA, Keith Gavin.

He added: "The IPA does not accept that making car access to the city centre more difficult will simply cause people to switch to other modes of transport.

"People who want to shop by car will travel to other destinations or shop online, taking money out of the city centre and economy."

Last June, the city council unveiled plans to restrict traffic through the city to avoid a repeat of the severe pressure that the capital endured during the boom.

The Dublin City Centre Transport Plan said the number of trips forecast into the city was expected to increase by 20pc by 2023 and warned that the road network simply could not cope with the extra traffic.

The main changes proposed include closing College Green to cars, vans and taxis; closing Bachelor's Walk between Jervis Street and O'Connell Street to private cars, and at either Aston, Burgh or George's Quay, and only allowing local access to Westmoreland Street and D'Olier Street.

In addition, the number of car-parking spaces will be reduced and visitors will be encourage to use public transport or a multi-storey car park at Heuston Station.

Retailers and car park owners have told the city council that if the measures are implemented, they will drive traffic to out-of-town shopping centres.

A survey for the IPA found that car users spend an average of €134 per visit, compared to €94 for bus passengers and €71 for pedestrians, which highlights their importance to the city's economy.

Taxi drivers have also expressed concern, saying that hotels in particular would suffer.